This invention relates to voice distribution and switching and, in particular, to combining voice distribution and switching with video distribution on a broadband coaxial cable network.
In U.S. patent applications Ser. Nos. 635,751 and 805,388, assigned to the same assignee hereof, there is disclosed an improved system for providing voice and video distribution over a cable network. In the systems of these applications, a plurality of telephone user or subscriber locations are provided and each subscriber location has an associated RF transmitting channel and an associated RF receiving channel. These channels carry voice and signalling information to and from, respectively, the subscriber locations.
A broadband cable network communicates with the subscriber locations and carries or couples with the associated RF transmitting and receiving channels. The cable network also communicates with a centralized switching and control means which is adapted to enable the RF transmitting channels to be selectively coupled or switched to any of the RF receiving channels. As a result, voice communication between the associated subscriber locations of the coupled channels can be carried out.
The particular switching means disclosed in the '751 and '388 applications comprises a time division multiplex (TDM) switch and a frequency/time conversion means. The latter conversion means establishes transmitting and receiving TDM digital channels corresponding to the transmitting and receiving RF channels so as to permit switching between channels by the TDM switch. Also, in the systems of these applications, the RF transmitting and receiving channels are analog channels organized into broadband RF channels of the cable network. Each user location, in turn, is assigned and couples with the broadband RF channel or channels containing its associated transmitting and receiving channels.
In the systems of these applications, the RF broadband channels also include channels for coupling video signals to TV's at the subscriber locations as per standard cable TV (CATV) operation. This provides the dual capability of video and voice over the cable network.
In the standard CATV operation contemplated in the systems of the '751 and '388 applications, the video signals originate via the cable network provider. The video signals are, thus, limited to signals originating from cable company sources and transmitted downstream to the subscriber locations.
It is, therefore, an object of the present invention to provide an improved system for integrated distribution of voice and video on a cable network.
It is a further object of the present invention to provide a system for integrated distribution of voice and video on a cable network which provides additional flexibility for the transmission of video signals than that offered by the systems of the '751 and '388 applications.